(1) [Field of the Invention]
The present invention relates to an internal grinding machine for grinding the inner surface of a work piece or work and, more particularly, to an internal grinding machine which is suitable for use in the grinding of a work which has to be finished with a specific high degree of precision and especially as regards a work which is desired to be finished to a particular level of cylindricality and straightness.
(2) Description of the Prior Art]
In general, grinding a long bore such as that in a plunger barrel 1 (see FIG. 5) requires a long grinder shaft (referred to sometimes as a "quill" hereinafter); see, for example, member 18 in FIG. 1 having a relatively small diameter. More specifically, a high grinding effect is produced by a combination of an elongated quill 2 and a narrow grinder 3 (see FIG. 5). The grinding of the cylindrical bore takes a long time, with the grinder 3 projecting out of the work 1 by a sufficient amount as shown in FIG. 5.
The grinding of the work 1 having a long in the prior art bore, however, encounters a problem in that the inner peripheral surface of the work 1, particularly the inner surface of the distal end portion of the work 1 (see FIG. 6--Prior Art), is ground in a tapered form due to flexing of the quill and the grinder. This makes it difficult to obtain the desired level of cylindricality.
Under this circumstance, the present inventors have found that the grinding can be conducted with sufficiently high cylindricality, provided the path of traversing movement of the grinder 3 is so controlled and determined that the quill-grinder system is inclined in the region where the prior art quill-grinder system tends to flex.